US Patent 8,628,754: Claim Scope, Pulmonary Delivery Coverage, and Patent Landscape

US Patent 8,628,754 covers a high-efficiency pulmonary-delivery method using a dry-powder inhaler. Its independent claim requires simultaneous satisfaction of two performance thresholds: at least 50% of the receptacle’s dry-powder mass must reach the lungs, and at least 5 mg of active agent must reach the lungs in a single breath-activated administration. The dependent claims narrow the technology to low-tap-density, spray-dried, largely non-crystalline particles with fine-particle-size distributions suitable for deep-lung delivery.

The patent is directed to delivery performance rather than a specific active ingredient, device brand, disease, or formulation composition. That breadth creates potential relevance across inhaled small molecules, peptides, proteins, vaccines, and other agents, but infringement depends on proving the claimed in vivo delivery results.

What does US Patent 8,628,754 protect?

The patent protects a method of administering a dry-powder formulation from a receptacle to a subject’s respiratory tract in one breath-activated step.

The core limitations are:

Claim element	Scope
Delivery route	Pulmonary system and respiratory tract
Device	Dry powder inhaler
Activation	Single, breath-activated administration step
Receptacle	Receptacle containing a mass consisting of the particles
Lung delivery efficiency	About 50% or more of stored dry-powder mass delivered to the lungs
Delivered agent dose	About 5 mg or more delivered to the lungs
Particle density	Tap density of about 0.4 g/cm³ or less, or 0.1 g/cm³ or less
Deposition site	Primarily the deep lung under claim 4
Particle manufacture	Spray-dried particles under claim 5
Solid-state form	Non-crystalline agent under claim 6
Fine-particle fraction	At least 50% below 4.0 µm under claim 7
Larger fine-particle threshold	At least 75% below 6.8 µm under claim 8

The independent claim does not expressly require spray drying, low-density particles, a particular inhaler architecture, or a particular active ingredient. Those limitations enter through dependent claims 2 through 8.

How should claim 1 be construed?

Claim 1 is a result-focused method claim with several structural and procedural limitations.

The single-step requirement

The administration must occur in a single, breath-activated step. A device that requires multiple inhalations, manual loading between inhalations, or separate actuation and inhalation stages may fall outside the literal scope unless the entire sequence can be characterized as one breath-activated administration.

The phrase does not necessarily require a single inhalation for every possible device configuration, but a multi-step delivery protocol creates a material noninfringement argument.

The receptacle limitation

The receptacle must have a mass consisting of the particles. This language ties the claimed efficiency calculation to the powder originally stored in the receptacle. It is narrower than a general requirement that 50% of a loaded dose reach the lungs.

Potentially relevant receptacles include:

Unit-dose capsules
Blisters
Cartridges
Foils
Reservoir compartments
Pre-metered dose containers

A reusable reservoir inhaler may present a claim-construction issue if the device does not deliver a discrete receptacle dose or if the claimed mass cannot be reliably identified.

The 50% lung-delivery threshold

The claim requires delivery of about 50% or more of the dry-powder mass stored in the receptacle to the lungs. This is materially different from emitted dose or delivered dose at the inhaler mouthpiece.

A product can therefore satisfy a conventional emitted-dose specification while failing claim 1 if substantial powder remains in the device, capsule, mouth, throat, or upper airway.

The key evidentiary questions are:

What is the denominator: total powder in the receptacle or emitted dose?
Does "to the lungs" include tracheobronchial deposition, or only pulmonary deposition distal to the conducting airways?
Is the 50% value measured in a laboratory model, animal study, human scintigraphy study, or another validated method?
How is dose variability handled?
Does "about 50%" include a statistical tolerance around the threshold?

The 5 mg delivered-agent threshold

The claim requires at least about 5 mg of agent to reach the lungs. The relevant quantity is active agent, not necessarily total powder mass.

This distinction matters for formulations containing:

Carrier excipients
Stabilizers
Surfactants
Buffering agents
Porosity-forming excipients
Coatings
Encapsulating polymers

A formulation containing 5 mg of total powder but less than 5 mg of active agent would not meet the literal dose limitation. Conversely, a high-load powder with a smaller total dose may satisfy the claim if at least 5 mg of active reaches the lungs.

What do the dependent claims add?

How do the low-tap-density claims narrow the patent?

Claims 2 and 3 require particles with a tap density of about 0.4 g/cm³ or less and 0.1 g/cm³ or less, respectively.

Tap density is relevant to aerodynamic behavior, powder dispersion, and the ability to deliver a large mass without producing excessive geometric particle size. Low-density particles can have a relatively large geometric diameter while maintaining an aerodynamic diameter compatible with pulmonary deposition.

Claim 3 is narrower than claim 2. A product with a tap density of 0.08 g/cm³ may fall within both claims, while a product at 0.25 g/cm³ may fall within claim 2 but not claim 3.

Testing conditions can affect tap-density results. A defensible freedom-to-operate analysis should examine:

Tapping instrument and method
Number of taps
Initial powder volume
Humidity
Powder conditioning
Batch-to-batch variation
Whether the measurement uses the active formulation or an excipient-only sample

What does claim 4 protect?

Claim 4 requires delivery primarily to the deep lung and depends on claim 2. It therefore requires:

At least 50% lung delivery
At least 5 mg active-agent delivery
Tap density of about 0.4 g/cm³ or less
Predominant deep-lung deposition

"Primarily" is a relative term. The claim does not state a fixed percentage for deep-lung deposition. That creates an infringement and validity issue because a product must be evaluated against the specification’s disclosure and the applicable technical meaning of deep-lung delivery.

What does claim 5 protect?

Claim 5 covers spray-dried particles meeting the limitations of claim 2. Spray drying is a manufacturing limitation. It can be established through process records, particle morphology, residual-solvent data, formulation development records, or manufacturing testimony.

A particle manufactured by spray freeze drying, milling, controlled crystallization, or a different atomization process may avoid claim 5 while remaining potentially relevant to claim 1 or another dependent claim.

What does claim 6 protect?

Claim 6 requires a non-crystalline agent. This limitation can encompass amorphous or otherwise non-crystalline active material, depending on the patent’s specification and the construction adopted for "non-crystalline."

Relevant analytical methods include:

Powder X-ray diffraction
Differential scanning calorimetry
Solid-state nuclear magnetic resonance
Raman spectroscopy
Infrared spectroscopy

The claim concerns the physical state of the agent, not necessarily the entire powder particle. A particle may contain crystalline excipients while the active ingredient remains non-crystalline.

What do claims 7 and 8 protect?

Claims 7 and 8 impose particle-size distribution requirements:

Claim 7: at least 50% of particles have a fine particle fraction below 4.0 µm.
Claim 8: at least 75% of particles have a fine particle fraction below 6.8 µm.

These limitations require careful distinction between:

Geometric particle size
Aerodynamic particle size
Fine-particle fraction
Mass-based distribution
Number-based distribution
Cascade-impactor measurement

In inhalation technology, fine-particle fraction is commonly measured using an aerodynamic particle-size instrument, such as an Andersen cascade impactor or Next Generation Impactor. A product’s marketing specification may not match the claim’s measurement convention.

What is the likely patent family and ownership position?

US 8,628,754 is associated with the low-density pulmonary-particle platform developed for high-dose inhalation delivery. The technology is closely related to research and patenting around porous or low-density particles, spray-dried formulations, deep-lung deposition, and large-dose delivery.

The relevant competitive technology groups include:

Technology group	Typical protection
Low-density porous particles	Particle architecture, tap density, aerodynamic behavior
Spray-dried particles	Manufacturing process, excipient composition, morphology
Dry-powder inhalers	Airflow activation, dose loading, deaggregation
Inhaled insulin systems	Active ingredient, formulation, device, dosing method
Peptide and protein powders	Stabilization, amorphous state, particle engineering
High-dose inhalation products	Delivered-dose performance and dose uniformity
Deep-lung delivery systems	Regional deposition and aerodynamic diameter

The patent’s claims are method claims. They should be separated from composition patents covering the particles themselves and device patents covering the inhaler.

What patents protect competing pulmonary-delivery products?

Commercial dry-powder products generally rely on layered patent protection rather than one patent.

Afrezza and Technosphere-based delivery

MannKind’s Afrezza platform uses Technosphere particles and a breath-powered inhaler. Its patent estate has historically included claims directed to:

Inhaled insulin
Dry-powder formulations
Technosphere microparticles
Inhaler structure
Dose delivery
Pulmonary administration
Manufacturing methods

US 8,628,754 is potentially relevant to a product using low-density, spray-dried particles and a single breath-activated delivery process, but product-specific infringement would require comparison of the marketed formulation, receptacle, device operation, and clinical delivery data.

Exubera and earlier inhaled-insulin systems

Pfizer’s Exubera system used a different inhaler and formulation architecture. Its patent estate included formulation, device, cartridge, and dosing claims. Exubera was withdrawn commercially, but its patents remain relevant as prior art and as evidence of the technical distinction between device-level and formulation-level protection.

Generic and follow-on dry-powder inhalers

Generic products may avoid a broad method claim by:

Delivering less than 5 mg of active agent to the lungs
Using multiple inhalations
Using a different dose-loading configuration
Failing to meet the 50% receptacle-to-lung mass threshold
Using crystalline rather than non-crystalline active material
Exceeding the relevant tap-density threshold
Using a non-spray-dried process
Delivering primarily to the conducting airways rather than the deep lung

Avoidance of a dependent claim does not avoid claim 1 if the independent limitations remain satisfied.

Is US 8,628,754 listed in the Orange Book?

A method patent is eligible for Orange Book listing only when it meets FDA listing requirements and is tied to an approved drug product and an approved method of use. A patent directed solely to general inhaler performance or platform technology may not be listed for every product using the technology.

The relevant Orange Book analysis requires checking:

Listed patent number
Approved product
Patent-use code
Drug substance, drug product, or method-of-use category
Patent expiration date
Whether the patent was timely submitted
Whether the patent has been delisted or removed

A listed method-of-use patent could support a Paragraph IV certification if a generic applicant seeks approval for an overlapping use. A non-listed patent could still create infringement risk after approval, but it would not automatically create an Orange Book-based approval stay.

What Paragraph IV and litigation risks exist?

A generic applicant facing this patent could challenge it through:

Invalidity based on anticipation
Obviousness based on low-density particles and pulmonary-delivery references
Lack of written description
Lack of enablement for the breadth of agents and devices covered
Indefiniteness involving "about," "primarily," "deep lung," and "fine particle fraction"
Noninfringement based on dose, device operation, receptacle mass, or measurement method

The strongest invalidity arguments would likely focus on prior art disclosing:

A single breath-activated dry-powder dose
At least 5 mg pulmonary delivery
At least 50% delivery efficiency
Low-tap-density particles
Spray-dried or amorphous particles
Deep-lung deposition

The strongest infringement defenses would likely challenge the measurement basis for "to the lungs" and the absence of a discrete receptacle mass.

No settlement agreement or active Paragraph IV proceeding can be attributed to this patent from the claim text alone. FDA and court records must be matched to the patent number and the specific approved product.

When did US 8,628,754 lose exclusivity?

The patent term depends on its earliest effective nonprovisional filing date, any applicable patent-term adjustment, terminal disclaimer, and maintenance-fee status. For a patent in the family with a 2004 priority or filing position, the ordinary 20-year term would place expiration in or around 2024 or 2025.

The critical commercial point is that the patent is unlikely to provide a long remaining exclusionary period for a current development program. Any present-day risk assessment should focus on:

Whether the patent has expired
Whether a terminal disclaimer links it to a later-expiring patent
Whether continuation patents preserve materially similar claim scope
Whether related device or formulation patents remain active
Whether foreign counterparts have different expiration dates

Patent expiry would eliminate infringement liability for the expired claims, but it would not eliminate active rights in continuation, divisional, or related patents.

How strong is the patent estate?

The patent is technically broad but legally vulnerable in several respects.

Strength factor	Assessment
Active ingredient coverage	Broad
Device coverage	Limited to dry-powder, breath-activated use
Formulation coverage	Broad in claim 1; narrower in dependent claims
Dose threshold	Concrete and potentially enforceable
Performance threshold	Difficult to prove consistently
Low-density particle coverage	Stronger in claims 2 and 3
Spray-drying coverage	Narrower but technically identifiable
Deep-lung coverage	Potentially indefinite without a defined threshold
Generic design-around risk	Significant
Remaining commercial value	Dependent on unexpired continuations and product-specific patents

The patent’s most commercially meaningful limitation is the combination of high lung-delivery efficiency and at least 5 mg of delivered active agent. That combination can be difficult for a competitor to avoid if it markets a high-dose, low-density powder intended for single-breath deep-lung delivery.

Key Takeaways

US 8,628,754 is a method patent for high-dose, high-efficiency pulmonary delivery from a dry-powder inhaler.
Claim 1 requires at least 50% of the receptacle’s powder mass and at least 5 mg of active agent to reach the lungs in a single breath-activated step.
Claims 2 through 8 narrow the scope to low-tap-density, deep-lung, spray-dried, non-crystalline, and fine-particle formulations.
The claims are not limited to insulin or any other named active ingredient.
Infringement analysis depends heavily on how lung delivery, fine-particle fraction, tap density, and receptacle mass are measured.
Commercial risk is more likely to arise from continuation patents, device patents, and active formulation patents than from this patent alone if its original term has expired.
Orange Book relevance depends on a specific approved drug product and an FDA-listed patent-use code.
Generic design-arounds can target dose, inhalation sequence, particle density, manufacturing process, receptacle configuration, or deposition location.

Frequently Asked Questions

Does US 8,628,754 cover all dry-powder inhalers?

No. It covers only methods meeting the claimed dose, efficiency, inhalation-step, and receptacle limitations. Ordinary dry-powder inhalers delivering lower doses or lower lung-deposition percentages may fall outside the claims.

Does the patent cover spray-dried inhaled insulin?

Potentially, but only if the product also satisfies the independent claim and the applicable dependent limitations. Spray drying alone does not establish infringement.

Can a product infringe claim 1 without infringing claims 2 through 8?

Yes. Claim 1 does not require low tap density, spray drying, non-crystalline active material, or the stated fine-particle fractions.

Are the 4.0 µm and 6.8 µm limits geometric particle sizes?

Not necessarily. The meaning depends on the patent specification and the applicable test method. Inhalation-product analysis commonly distinguishes aerodynamic size from geometric size.

Do expired claims still block FDA approval?

No. Expired claims cannot support a new patent-infringement exclusion. FDA approval may still be affected by unexpired patents, listed use patents, exclusivity periods, or other regulatory requirements.

References

United States Patent and Trademark Office. (2014). Methods of delivering an agent to the pulmonary system, U.S. Patent No. 8,628,754.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.
U.S. Food and Drug Administration. (2024). Approved drug product with therapeutic equivalence evaluations: Patent and exclusivity information. FDA.
United States Patent and Trademark Office. (2024). Manual of patent examining procedure: Patent term adjustment and patent term expiration. USPTO.
United States Code, 35 U.S.C. §§ 154, 271, 282.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	357222	⤷ Start Trial
Australia	2001275368	⤷ Start Trial
Australia	7536801	⤷ Start Trial
Canada	2412561	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,628,754

Summary for Patent: 8,628,754